Fill support for closed annotations (polygons, rectangles)

[insertmike]

Fill Support for Closed Annotations

It would be nice to add fill support for annotations where the start and end points connect (e.g., polygons, rectangles). This would also partially address Issue #159. Was this considered during feature planning and are there any plans to support this in future releases?

[flekschas]

I agree it'd be a fantastic feature. Feel free to take a stab at it. This would require a function to render closed polygon shapes which does not exist at the moment.